常用基数词与序数词
1.one—first 2.two—second
3.three—third 4.four—fourth
5.five—fifth 6.six—sixth
7.seven—seventh 8.eight—eighth
9.nine—ninth 10.ten—tenth
11.eleven—eleventh 12.twelve—twelfth
13.thirteen—thirteenth 14.fourteen—fourteenth
15.fifteen—fifteenth 16.sixteen—sixteenth
17.seventeen—seventeenth 18.eighteen—eighteenth
19.nineteen—nineteenth 20.twenty—twentieth
21.twenty-one—twenty-first
22.twenty-two—twenty-second
23.twenty-three—twenty-third
24.twenty-four—twenty-fourth
25.twenty-five—twenty-fifth
26.twenty-six—twenty-sixth
27.twenty-seven—twenty-seventh
28.twenty-eight—twenty-eighth
29.twenty-nine—twenty-ninth
30.thir1ty—thirtieth
31.thirty-one—thirty-first